> isn’t it an instantaneous thing and not something you need to extinguish? I'm not familiar with the details of this accident, but in general, not necessarily

> isn’t it an instantaneous thing and not something you need to extinguish? I'm not familiar with the details of this accident, but in general, not necessarily. Air is normally an excellent insulator. But when voltages are high enough, the molecules ionize, become conductive and transmit current. This is a path-dependent process, meaning that once it begins, the voltage can drop below what is required to begin the process while maintaining current. So an arc caused by a system with low capacitance (or total count of free electrons on the negative side) may quickly transfer all the free electrons, lowering the voltage enough to close the circuit. But anything connected to mains power will have an essentially infinite source of more electrons, meaning there won't be a voltage drop big enough to close the circuit. I'm being a little handwavy with the physics concepts, but hopefully the point is clear. This can be thought of as a sort of hysteresis: the dependence of the state of a system on its history. Edit: If you want to go down a rabbit hole, check out the solutions used in power substations as circuit breakers. It's not enough just to mechanically separate the connection, so they use systems like these: https://en.wikipedia.org/wiki/Sulfur_hexafluoride_circuit_breaker https://en.wikipedia.org/wiki/Sulfur_hexafluoride_circuit_br... https://www.codrey.com/electrical/air-blast-circuit-breaker/ https://www.codrey.com/electrical/air-blast-circuit-breaker/